/fast {on|off|status} goes through to chat rather than being handled by the internal command processor

[tbreeds-nv]

What version of Codex CLI is running?

codex-cli 0.142.5

What subscription do you have?

nvidia?

Which model were you using?

gpt-5.5

What platform is your computer?

Linux 5b77c80-lcelt 6.17.0-35-generic #35~24.04.1-Ubuntu SMP PREEMPT_DYNAMIC Tue May 26 19:30:42 UTC 2 x86_64 x86_64 x86_64 GNU/Linux

What terminal emulator and version are you using (if applicable)?

gnome-terminal

Codex doctor report

What issue are you seeing?

When running /fast off the message is going through to the chat like a normal message rather than being handled as a command. Same with /fast status. I can use /fast as a toggle but that doesn't match the documentation.

What steps can reproduce the bug?

Uploaded thread: 019f1b4c-5f68-71a2-83be-548fbcca0918

What is the expected behavior?

/fast off should disable Fast mode.
/fast status should report whether Fast mode is on or off.
Neither command should be sent to the assistant as chat text.

Additional information

Docs say /fast on, /fast off, and /fast status are valid

Repro steps

1. Start codex-cli 0.142.5.
2. Confirm banner shows gpt-5.5 xhigh fast.
3. Type /fast off at the start of the TUI composer.
4. Observe it is submitted as a normal chat message.
5. Repeat with /fast status.

[github-actions]

Potential duplicates detected. Please review them and close your issue if it is a duplicate.

• UX footgun: /feedback <text> can be routed like a normal prompt instead of opening or pre-filling the feedback flow #30603

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[ArturBieniek4]

I also encountered this problem.

I verified this against the current sources, and this is a regression.

/fast used to be a hardcoded built-in slash command. In 2f5b01a, it supported:

/fast [on|off|status]

The regression appears to come from 7c0e54b, which generalized service-tier slash commands and removed the hardcoded /fast command. Bare /fast still works, but
dynamic service-tier commands currently report supports_inline_args = false, so /fast off and /fast status are not parsed as commands and fall through as regular prompt text.

I made a small patch that restores inline-argument handling for dynamic service-tier commands. It adds coverage for:

• /fast off resetting the service tier to default
• no user turn being submitted for /fast off
• typed composer/popup dispatch of /fast off
• queued slash-command dispatch

I am not able to open a PR, so I am attaching the patch here instead. The patch was entirely vibecoded using Codex.

Patch attached:

codex-fast-off-regression.patch

Validation run locally:

just fmt
just test -p codex-tui fast_slash_command_off_arg_disables_fast_without_user_turn
just test -p codex-tui service_tier_slash_command_with_args_dispatches_from_catalog_name
just test -p codex-tui

Final package test result:

2952 passed, 4 skipped

[abhay-codes07]

Confirmed and fixed. Bare /fast toggles, but /fast off and /fast status fell through to the model as chat because service-tier commands reported no inline-argument support (SlashCommandItem::supports_inline_args returned false for the ServiceTier variant), and both dispatch paths only accepted builtin commands with arguments, so the service-tier-with-args case landed on the submit-as-user-message fallback.

Fix: treat service-tier commands as inline-arg commands and route the argument to a dedicated handler. on/enable set the tier explicitly (the bare command toggles, which is why on/off are the useful spelling), off/disable reset to the default, status reports the current state, and anything else prints a usage hint. Both the immediate composer path and the queued path (commands typed while a turn is running) are covered.

Tests: a direct handler test covering on/off/status, plus a composer-routing test that submits /fast off and asserts it resets the tier as a command rather than being sent as chat (the buggy path would not emit the tier override). The tui suite passes, and rustfmt and clippy are clean.

Branch: https://github.com/abhay-codes07/codex/tree/fix/fast-slash-command-args

External PRs are invite-only here, so I am leaving it as a branch; happy to open one.